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John Deere GP

John Deere GP tractor
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The John Deere GP was produced from 1928 to 1935 as a row-crop tractor in the Two-Cylinder Letter Series. It was designed as a general purpose tractor with a fixed front axle straddling three rows. Several versions existed including the wide-tread GPWT, the potato field GP-P, and the orchard GPO. The GP featured a two-cylinder kerosene engine available in 5.1L and 5.6L variants, a 3-speed unsynchronized transmission, and was capable of pulling two 14-inch plows. It was built in Waterloo, Iowa, USA, with over 30,000 units produced. The tractor had an open operator station, manual steering, and two-wheel drive.
John Deere GPtractorspecificationsenginetransmissiondimensionspowervariantsfarm tractor
Power20 hp[B]
Founded1928 - 1935
ModelGP

Technical Specifications

Detailed specifications and technical data for John Deere GP

Power

Plows:2 (14-inch)
Belt (tested):25.36 hp (18.9 kW)
Belt (claimed):20 hp (14.9 kW)
Drawbar (tested):18.86 hp (14.1 kW)
Drawbar (claimed):10 hp (7.5 kW)

Tires

Rear tire:42.75x10 steel, 10.00x32
Front tire:24x6 steel, 6.00x16

Engine

Aux. fuel:2 gal (7.6 L)
Fuel tank:16 gal (60.6 L)
Details 5.1L:John Deere kerosene 2-cylinder liquid-cooled inline. Original engine, used until 1931. Water-injection system was used to prevent detonation ("knocking") with low quality fuels.
Details 5.6L:John Deere kerosene 2-cylinder liquid-cooled. The new engine was introduced in 1931 on GP serial number 224100. It had lower compression but with a quarter-inch larger bore, producing slightly more power with better fuel economy. The lower compression eliminated the pre-ignition problem when using low-quality fuel, so the water-injection system was eliminated.
Engine options:John Deere 5.1L 2-cyl kerosene, John Deere 5.6L 2-cyl kerosene
Rated RPM 5.1L:900
Rated RPM 5.6L:950
Bore/Stroke 5.1L:5.75x6.00 inches (146 x 152 mm)
Bore/Stroke 5.6L:6.00x6.00 inches (152 x 152 mm)
Displacement 5.1L:311.6 ci (5.1 L)
Displacement 5.6L:339.3 ci (5.6 L)
Coolant capacity 5.1L:36 qts (34.1 L)
Coolant capacity 5.6L:36 qts (34.1 L)

Variants

GPO:orchard
GP-P:potato
GPWT:wide-tread

Dimensions

Height:55.5 inches (140 cm)
Length:112 inches (284 cm)
Weight:3,600 lbs (1632 kg)

Mechanical

Drive:Two-wheel drive
Steering:Manual steering
Operator station:Open operator station

Production

Built in:Waterloo, Iowa, USA
Description:The GP was originally designated the Model C, the name was changed due to a similarity to the existing D, plus the "General Purpose" name was a marketing ploy to keep in line with International's new "Farmall". The GP was designed as a row crop tractor, with the fixed front axle straddling three rows. Several versions of the GP were made. The "wide tread" GPWT has a 76-inch rear axle and a tricycle front. The GP-P was a modified GPWT with a 68-inch rear axle, for use in potato fields. The GPO was lowered and had fenders for orchard work. Twenty-four GPO tractors were converted into crawlers by Lindeman.
Total built:30,535 (GP), 5,103 (GPWT), 717 (GPO)
Manufacturer:John Deere
Original price:$1,200 in 1935

Transmission

Type:unsynchronized gear
Gears:3 forward and 1 reverse